A Wall Street banker raped a student in a "disgusting, violent attack" because he was determined to have sex on his birthday, a court heard.

Jason Lee forced himself on the 20-year-old in a bathroom and told her to "shut the f*** up" so her friends in the next room would not hear.

He also put his hand over her mouth so hard that she could not even bite him, the Irish Mirror reports.

The assault ended when the girl kneed him in the groin and staggered out in such a hysterical state she was unable to talk.

Lee tried to downplay the alleged assault and said it was "no big deal" and dismissively told the first police officer on the scene: "We're good, you can go".

The rape allegedly happened when Lee, 38, invited the victim and her friends to party at his rented $33,000-a-month mansion in The Hamptons on Long Island, New York during the summer of 2013.

On the first day of the trial, Kerriann Kelly, the Chief of the Major Crime Bureau at Suffolk District Attorney's office, said that Lee and his victim were "from such different worlds that they might have been from different planets".

She had spent the summer in New York on a J-1 visa and was staying with her brother for a night out before flying home to Ireland.

Lee was a high flying executive at Goldman Sachs who lives in Manhattan, but Miss Kelly said: "What you see is not always what you get".

She told the court: "What you see in the court room this morning is a defendant dressed in a very professional suit, his hair is nicely combed. He is copiously taking notes as I speak.

"That's not the same individual the victim encountered in the early morning of August 20 2013. Not even close.

Accused: Jason Lee arriving with his wife at Suffolk County Criminal Court

"What she encountered was a man who wanted one thing and one thing only, and that thing was sex. He used her to get it."

Lee has denied first-degree rape, sexual misconduct and third-degree assault and could face 25 years in jail if convicted.

He walked into Suffolk District Court wearing a dark suit hand in hand with his wife Alicia, who sat in the public gallery.

The court was told that Lee and his friend Rene Duncan met the victim and her friends at the trendy Georgica restaurant and lounge in Wainscott on August 19 2013.

The two men were there celebrating Lee's 37th birthday and they invited the Irish group back to his mansion a short distance away.

Miss Kelly said that they having a good time partying the night away, drinking wine and eating pizza they found in the freezer.

The victim and her female friend stripped down to their underwear and got in the pool but Lee got completely naked and jumped in after them.

Afterwards, around 6am, the victim went into a downstairs bathroom to change, and she "became aware that Jason Lee was trying to force his way into the bathroom by pushing open the bathroom door," Miss Kelly said.

"The victim saw him, he was naked, and she thought: 'Is this a joke?' She pushed back and said: 'What do you think you're doing?'"

Miss Kelly said that the victim pushed so hard she left her fingerprints on the door, but Lee was too strong and forced the door open.

As he did so she went flying onto her back, hurting her hip and scratching her leg.

Miss Kelly said: "Now he had her exactly where he wanted her, on the floor, on her back and he climbed on top of her and he held her down."

Rape charge: Jason Lee

The victim tried to shove him off but she was unable to.

Miss Kelly said: "She asked him to get off her. She told him: 'No'

"The defendant put his hand over her mouth and held his hand down so hard that the victim tried to bite him but was unable to.

"Then he told her to shut the f*** up, shut the f*** up.

"He didn't want anyone to interrupt what he wanted to do at that time and in that place - on his birthday."

Miss Kelly described how Lee pulled up her dress, pulled down her underwear and raped her.

She said: "He had no regard for her.

"He had no condom and 37-year-old Jason Lee you see before you here had no regard for the 20-year-old Irish girl who was just visiting [her brother].

"He took advantage of her because he wanted to have sex and because he was going to do whatever he had to do to get it."

Miss Kelly said that the attack only stopped when the victim managed to knee him in the genitals, making him "back off in pain".

As she walked out of the bathroom the victim was "hysterical and crying," Miss Kelly said.

Miss Kelly said: "She couldn't say what was wrong to her.

"Her brother was upset and said: 'What's happened to my sister? What went on in that room?'

"The victim couldn't speak she was so hysterical."

Suffolk County Criminal Court: The banker appeared today

The police were called by Mr Duncan because he thought that his car had been stolen, though the court was told that he had actually loaned it to some of the victim's friends who had left earlier.

During the call to the 911 dispatcher Lee allegedly said: "It's not big deal, there is no problem here, we don't need you to come to this house."